Female Arousal and Orgasm: Anatomy, Physiology, Behaviour and Evolution

By Donald Lambert Jesse Quicke

Female Arousal and Orgasm: Anatomy, Physiology, Behaviour and Evolution is the first comprehensive and accessible work on all aspects of human female sexual desire, arousal and orgasm. The book attempts to answer basic questions about the female orgasm and questions contradictory information on the topic. The book starts with a summary of important early research on human sex before providing detailed descriptions of female sexual anatomy, histology and neuromuscular biology. It concludes with a discussion of the high heritability of female orgasmicity and evidence for and against female orgasm providing an evolutionary advantage.

The author has attempted to gather as much information on the subject as possible, including medical images, anonymized survey data and previously unreported trends. The groundbreaking book gives a scientific perspective on sexual arousal in women, and helps to uncover information gaps about this fascinating yet complex phenomenon.

Readership
Biologists, general readers, psychologists

• Language: English
• Publisher: Bentham Science Publishers
• Release date: Mar 20, 2001
• ISBN: 9789815124637

Book preview

Introduction

Donald Lambert Jesse Quicke

Sex in western society went through a rather taboo period in the 19th and first half of the 20th century. It wasn't talked about much in 'polite circles', and female sexual pleasure and gratification were relatively less discussed and understood. It was in the USA following World War II when a few academic researchers started to apply sociological and scientific methods to the topic. Three questions started to be addressed: (i) What do people do 'in bed', (ii) how often, and (iii) what actually happens anatomically, physiologically and psychologically? The landmark names are Alfred Kinsey (1894–1956), William Masters (1915–2001) and Virginia Johnson (1925–2013), and Shere Hite (1942–2020). Although these were by no means the first researchers to study sex, the sheer size of their studies and the public attention their studies received set them apart. There are also a few, and I generally think under-rated, studies before them, and of particular note should be the detailed, thoughtful and extensive work on female reproduction by Robert Latou Dickinson [10, 11], which considered a very wide range of topics, from the genitals of prostitutes, to where the penis stimulates in different sex positions and where the semen goes in relation to the cervix.

Unlike most researchers today, who are obliged to publish scientific papers in peer-reviewed journals, at what seems like an ever-increasing rate, in order to keep their jobs, these earlier workers, although publishing a few separate papers in scientific journals, generated such voluminous amounts of data that their most important outputs were in the form of books. It is hard to imagine anyone in the current competitive academic climate being able to do that. Indeed, many have commented that neither Charles Darwin's or Albert Einstein's productivities in peer review journals would secure their tenure in top universities in the current age. We must be thankful that Kinsey, Masters and Johnson, and Hite were able to produce their works because they changed so much for the better.

It must be emphasised that societal norms back in the 1950s and 60s were not the same as they are today. A lot of the sexological research back then was coloured to some extent by expectations about social groups, whether the sex was conducted within a married relationship, etc. The past 20 or 30 years have seen a great deal more exposure to sex, sexual practices and sexual expectations in the

mainstream media, though often without correct terminology, and so people who reached adulthood during these times might be expected to have had a rather greater awareness of sex practices. In a way, Bose, back in 1937, must be applauded for going against the dogma of the time that there are major racial/skin-colour related differences in 'potency' [12].

Not just sex research but also medical and anatomical publications reflect taboos against anything to do with the sex [13]. There has also been enormous gender bias in both general and medical sex research. Studies on men and male impotence and its potential cure vastly outnumber studies on womens' sexual responses and dysfunctions. Research has gradually been correcting some of this imbalance, but even as recently as 2010, the French gynaecologist Odile Buisson [14] made a point of criticising the French university system in general for showing marked androcentrism and for failing to develop female sexual medicine sufficiently, even for deliberately ignoring it because of their male-dominated views and taboos.

Sex researchers, at least during the early years, tended to be university academics which has had and still has a profound influence on the subjects who participate in their research [15]. With large numbers of undergraduate and postgraduate students at hand, simply posting adverts for volunteers on university noticeboards or newsletters was often enough to get ample research participants. Indeed, Alfred Kinsey and others were often surprised by how readily many, especially female, students, were willing to take part in their studies. Whilst, not a large proportion overall, it likely indicated that these volunteers were aware of the dearth of medical/scientific knowledge about female sexuality at that time. More recently, a far larger proportion of researchers have come from more or less purely medical backgrounds reflecting increasing attention paid by their profession on female sexual medical and psychological problems and also the associated, still incomplete anatomical and physiological knowledge of the subject. It is far harder to recruit subjects from the general population. Advertisements in local newspapers get some, and more recently, the internet has allowed a prudent approach to a far greater potential audience when it comes to gaining responses to questionnaires. The vast majority of participants in actual physical research, however, tend to be young university or nursing-associated subjects, or women seeking medical appraisal. A bimodal and non-random sample.

However, there are many obstacles to be overcome even to start research on human sex, and also on sex in some other mammals. I recall many adverse comments concerning a postdoc who was working on sex in rats whilst I was an undergraduate at Oxford. As Pfaus [16] put it:

"Doing sex research sometimes feels like stumbling into a Kafka novel where unlocking heavily guarded secrets of the sexual universe are a subversive act met with resistance, deterrence, and retribution. In addition to roadblocks put in place by risk-averse granting agencies and downright terrified academic administrators and their media minions, sometimes the subject itself eludes capture by a plethora of perfectly reasonable experiments that, when taken together, overwhelm us with conflicting information."

Without a doubt, much harm has been done as a result of Sigmund Freud's [17] theories on female sexuality, and a great deal has been written on this, e.g., [18, 19, 20, 21]. Briefly, Freud argued that the attachment of a girl to her mother meant that her early sexual arousal and orgasm experience, which was typically largely focused on her clitoris, was juvenile (even homosexual), and that they must make the transition to having orgasms through heterosexual vaginal penetrative sex in order to be properly adult. If they did not, he labelled them as 'frigid', a stigmatisation that caused many women much anguish and hurt. There have been many good discussions of Freud's theories and how subsequent research, especially starting with Alfred Kinsey and Masters and Johnson, led to major changes in views.

Alfred Charles Kinsey

Alfred Charles Kinsey (Fig. 1.1) was an entomologist like myself, indeed, a world expert on gall wasps and responsible for amassing a truly enormous collection of them which is now housed in the American Museum of Natural History, New York. He was a full professor at Indiana University. However, he developed a sideline interest for which he was to become most famous, human sexuality and sex research. This led him found the Institute for Sex Research at Indiana University in 1947; the institute is now known as the Kinsey Institute for Research in Sex, Gender, and Reproduction, or just the Kinsey Institute for short. His key publications were on sexual behaviour in the human male [22], and, more relevant here, on sexual behaviour in the human female [23]. Although not the absolute first academic to become involved in this type of research, his studies were certainly revolutionary. Nearly all of the previous research was largely carried out from a medical perspective and carried out by physicians. Indeed, one of Kinsey's predecessors, Havelock Ellis, wrote that he studied medicine specifically because it was the only profession in which one could study sex safely. Kinsey brought a very different descriptive taxonomic approach to sex research, in concordance with his other line of research, insect taxonomy [24].

Kinsey applied for and received an exploratory grant to start his new research venture in 1941, to cover the costs of interviewing many respondents in person. Over the course of his now famous research, he actually personally conducted over 8,000 of the interviews and his research team a further 10,000. Towards the end of his exploratory grant, the funding agency asked one of its physician members to visit Kinsey and appraise his research to date., The appraiser, Dr. George W. Corner, wrote in his autobiography [25: p. 268]:

He was a full professor, married with adolescent children. While carrying on his teaching duties in the zoology department, he worked every available hour, day and night, traveling anywhere that people would give him interviews. He was training a couple of young men in his method of interviewing. Dr. Yerkes and I submitted separately to his technique. I was astonished at his skill in eliciting the most intimate details of the subject's sexual history. Introducing his queries gradually, he managed to convey an assurance of complete confidentiality by recording the answers on special sheets printed with a grid on which he set down the information gained, by unintelligible signs, explaining that the code had never been written down and only his two colleagues could read it. His questions included subtle tricks to detect deliberate misinformation.

Fig. (1.1))

Alfred Charles Kinsey photographed in 1955, taking part in a press conference during an airport stop-over in Frankfurt. (Source: public domain).

Needless to say, Kinsey received further funding.

There is much interest in Kinsey's research, and he has been the subject of stage plays, even a musical and a film. On the other hand, it has been criticised because of his approach and failure to adjust methodologies, instead just gathering more and more of the same type of information. There has also been a long-running anti-Kinsey campaign, and even in these more liberal years, there is still political opposition to sex research in many areas. These attacks included allegations of scientific fraud [26], and potentially more seriously, of child abuse by Kinsey as the basis for some of the information presented in the first book [22]. He also encountered considerable opposition even from within his own university department because, as a scientist, he did not try to impose moral views [24]. I must make it clear here that neither Kinsey, nor his co-authors, were involved in any way with child abuse, as was proven by John Bancroft, former director of the Kinsey Institute, who investigated the sources of data in the relevant tables of Kinsey et al.'s book on male sexual behaviour [22]. Any reader interested in the details, and indeed the whole politics of sex research, should consult Bancroft's excellent historical perspective piece [26].

Attempts to discredit and demonise Kinsey included that his work promulgated liberal and pro-homosexual views that threatened the heterosexual, monogamous family. This campaign appears to have been started by Judith Reisman in the early 1980s, eventually leading to two books [27, 28]. Quoting from the first of these, as did Bancroft, you will get an idea as to how nasty the attacks were:

"Kinsey and his funders have largely succeeded in drastically debasing our fathers and lowering our moral life, which can only be restored by eradicating all traces of the Kinsey fraud from all facets of American life and terminating public funding of programs based on Kinsey's 'grand scheme'".

As you can see, the authors of the two anti-Kinsey books are strong proponents of the monogamous family. This may be seen as a backlash, or retreat from, the liberalism of the sexual revolution of the 1970s. Bancroft [26] asks why the attacks were so vicious. Reisman's primary motivation seems to have been her moral belief that children were, and should be, asexual and pure, while Kinsey had clearly shown the opposite. The support that the campaign received from others, though, could have been due to this. Further, people, especially political conservatives, were upset or even horrified by the apparently far higher incidence of homosexuality than they wanted to believe could be true.

Incidentally, the second author of the second Reisman book was Edward Eichel, whom we will meet again in Chapter 9 on his 'coital alignment technique'.

William Masters and Virginia Johnson

William Masters was a gynaecologist working at Washington University in St. Louis. He hired Virginia Johnson as a research assistant in 1957 to undertake a comprehensive study of human sexuality (Fig. 1.2). To do so, they paid volunteers to engage in sexual activity in their lab whilst various aspects such as heart and breathing rates or female lubrication, were recorded. During the course of their work, they observed nearly 700 people either masturbating or having sexual intercourse [29], and the total number of sexual acts they observed amounted to nearly 10,000.

For their early research, their subjects included, or were mostly local sex workers, but as the research progressed, they typically studied sexual intercourse between white heterosexual married women with a random male sex partner(s) [29]. In addition, Masters and Johnson also engaged in intercourse as subjects of their own study, and eventually, they became lovers despite Masters being married to someone else [30]. After divorcing his first wife in 1971, Masters married Johnson. They later divorced in 1993 but continued to work together at the independent not-for-profit research institution they founded, also in St. Louis.

Masters and Johnson concluded unequivocally that vaginal orgasms and clitoral orgasms were if not one and the same entity subjectively, very similar on a physiological level [31]. This conclusion had an enormous impact because it overturned decades of psychological and psychiatric scholarship that started with Sigmund Freud. Up until then, it was believed that clitoral orgasms were a juvenile type and that women needed to move the site to their vaginal canals 'where adult women had them'. For a long time, women had been told by health and medical professionals that if they did not manifest orgasm transfer, they were frigid! If women were not able to have vaginal orgasms on their own, it sometimes led to them seeking or being prescribed, psychiatric treatment/therapy.

Although quite a few of Masters and Johnson's results had been known from previously published research, this had received relatively little attention until their book was published [32]. However, their major contribution was their now classic, four-stage sexual model of sexual response comprising excitement, plateau, orgasm(s) and resolution; sometimes called the EPOR model. Although the names have sometimes been modified, for example, to include an earlier desire phase [33], it is still very much the standard picture (see Orgasm Research and the Model Orgasm, Chapter 5). Some variants have been proposed subsequently, primarily to take into account additional aspects, notably psychological factors [34], and these resulted in the circular model of Basson

[35], but the four essentially physiological phases of Masters and Johnson are still relevant.

Fig. (1.2))

William Masters and Virginia Johnson. (Source: reproduced by permission of the Kinsey Institute and Scott Johnson).

Despite Masters and Johnson, and many others, declaring that clitoral and vaginal orgasms are one and the same thing [31], many women seem to disagree, and so too do quite a few sexologists [36]. In Chapter 11 I explore whether there is any evidence, either subjective or physiological, that differences do exist even if they do not manifest themselves as conspicuously different patterns of physical response or in current studies of brain response.

As with Kinsey's [23], Masters and Johnson's [31] work has not, however, gone without some criticisms, corrections and revisions, for example, [37, 38, 32]. Some accusations are highly questionable, Levin [39], for example, comments on an attempt by Brody et al. [40] to discredit most of their work as follows:

"Brody et al. (2012) employ a hearsay report (purported to come from the ill and aged Virginia Johnson) in an un-refereed book by an investigative journalist author (Maier, 2009) that Masters faked some of his results. This, Brody et al. (2012) propose, leads them to the remarkable conclusion that any other data obtained in their classic laboratory studies on the human sexual responses must also become suspect."

I have no doubt that Masters and Johnson's seminal book does not contain any fakery.

Shere Hite

The feminist movement that started in the 1960s was emboldened by much of the then-new sex research, see for example [20]. Following the publications of Alfred Kinsey, and the biological studies of Masters and Johnson, the obvious next step was to try to discover what sexual practices women actually do and how they do them. This challenge was taken up by Shere Hite (Fig. 1.3), a feminist and sex educator. She was born an American, but later, in 1995, she renounced her United States citizenship, to become a German citizen with a brief period in between when she was technically a stateless person. She related her findings to the feminist movement, for example, Anne Koedt's [19] feminist essay "The Myth of the Vaginal Orgasm".

Fig. (1.3))

Shere Hite in June 1981, author of The Hite Report, detailing accounts of sexual experiences and practices in a large sample of American women. (Source: photograph by Bernard Gotfryd, public domain).

Hite focused primarily on female sexuality and in 1976, she published the best-seller (more than 48 million copies sold worldwide), "Female Sexuality: A Nationwide Study of Female Sexuality" [41]. This 478-page book contains the self-reported results of about 3,000 of 100,000 questionnaires Hite distributed to women ranging in age from 14 to 78, when the topics of female sexuality and especially female masturbation were still largely taboo. As with some other writings on sexuality, such as the Kinsey Report and the work of Masters and Johnson, Hite’s book does contain some statistical analyses, but its greater part comprises candidly recounted anecdotes, opinions, and complaints, relating to the respondents’ sex lives. Reviewers roundly criticised Hite for lax statistical reporting (among other lapses, she failed to obtain demographic statistics from some of her respondents), but the book became an instant best seller. While flawed in its handling of statistics, it challenged numerous accepted notions about female sexuality. I think it is wrong to criticise it too much because her approach was to let her respondents answer the questionnaires in free form, and that makes it terribly difficult to score them with simple categorical or numeric answers. The Hite Report contains a treasure trove of information about practices at the time, and it was not conceived in the first place as a data collection exercise for a peer-reviewed publication.

Her surveys led Hite to conclude that 70% of women do not have orgasms through stereotypic in-out, penile thrusting intercourse, but are nevertheless easily able to reach orgasm via clitoris-focused masturbation or other direct clitoral stimulation. The importance of this was that with such a high proportion of women not orgasming through penile-vaginal sex, that alone should not be considered as sexual dysfunction, though that concept still persists today in the minds of some. Consequently, Hite offered that limiting test subjects to normal women who report orgasm during coitus was basing research on the faulty assumption that having an orgasm during coitus was typical, something clearly refuted by her data. She famously wrote:

"Researchers should stop telling women what they should feel sexually and start asking them what they do feel sexually."

Early Sex Researchers Summary

These pivotal early sex researchers, Kinsey, and Masters and Johnson, and Hite in the USA, plus Roy Levin in Denmark and then the UK, undertook their work on the basis of what was of interest to them, but things nowadays have changed. There is no longer the same freedom in academia for the sort of long-term research out of pure interest because grants, economics and publications in top peer-reviewed journals now play a far larger role in what is studied, indeed, these aspects are paramount. Scholarship, in the old-fashioned sense, is no longer valued in the modern university system.

There is nothing wrong per se with directed medical funding seeking treatments for sex-related disorders, and some of this can still be described as basic research. However, one consequence of this is that there are still many unanswered basic biology questions about women's orgasms and even their anatomy. Much sex research has actually been done on a shoestring budget, not infrequently funded out of the researchers' own pockets. Interestingly, much sex research conducted in the USA between 1914 and 1954 was supported not by government agencies or medical sources, but by the wealthy American Rockefeller family [42]. John D. Rockefeller was likely partly motivated to support sex research because of his Baptist background and concern for the poor and unfortunate, such as prostitutes, forced into the profession out of need.

For whatever reason scientists undertake to do sex research, it has its consequences. Many are stigmatised [15], and as mentioned above, Alfred Kinsey was accused (wrongfully) of child abuse. Thefore, sex researchers themselves must be motivated enough to put up with this. Obtaining research funding is also a problem. Some government agency funding has been and is being provided, but a lot of research in the past has been financed to a considerable extent by private donations. As Wiederman [15] points out, politics comes into this. And whilst that may have been more the case during the early days of sex research, it is still true today. Various political 'conservatives' still tend to oppose this type of research and its funding because they might not like the results, which in turn might seem to encourage behaviours that they disapprove.

What is Normal?

Masters and Johnson first proposed the idea that sexual response (their 'Sexual Response Cycle') comprises a linear progression through four phases: arousal (excitement), plateau, orgasm(s) and resolution [31]. This is discussed in more detail in Chapters 6 and 7. Their model is very much an observational one, based on the human body's physical and physiological responses and, even though it consequently has limitations, it is widely accepted within that context, and usually taken as a starting point. Of course, things do not always proceed in textbook fashion, and not only may orgasm not be reached at all (more so in, but not only in women), but excitement and orgasm can often occur without desire [43].

The above linear, biological types of model do not take into account psychological factors such as pleasure, intimacy, and satisfaction, nor features associated with human relationships. Helen Singer Kaplan proposed a simplified version, which simultaneously incorporated the concept of desire but only talks about three phases: desire, arousal and orgasm [44]. The integration of a cognitive aspect, desire or libido, was widely welcomed.

Rosemary Basson developed a circular model of the sex response [35, 45, 46], which further tried to integrate emotional and satisfaction features. She criticised the previous definitions of sexual disorders for ignoring various emotional factors that are important such as "... trust, intimacy, the ability to be vulnerable, respect, communication, affection, and pleasure from sensual touching" [47]. Of course, not everyone wants to be involved in relationships all of the time, and hence affairs, as well as the oldest profession, may help in these cases.

It has only become apparent to the scientific community that women may show genital responses in the absence of any subjective experience of sexual arousal, which demonstrates a separation or disjunction between their psychological and physical states with the subconscious processing of stimuli [2, 48].

Although there are obvious differences between male and female orgasms, subjectively, they appear to be identical. When Vance and Wagner [49] obtained descriptions of orgasm written by men and women with all obvious gender clues removed, and presented them to both men and women, the readers are unable to tell whether the descriptions were written by men or women. Both sexes, therefore, appear to experience the same mental experience of orgasm. This appears to be well-confirmed in a subsequent study by Mah and Binik on the adjectives that men and women use to describe their orgasms (Appendix A); the only significant differences between sexes were in the responses to the shooting sensations term, which seems likely to have between due to male ejaculation [50].

There are certainly gender differences in orgasm apart from the obvious ejaculation of semen by the male. A good proportion of women but only a very small proportion of men, especially as they get older, can experience multiple orgasms. In some women, it seems that the ability to be multi-orgasmic can be learned, though this may take some practice over a considerable period of time [51]. It has been proposed that all orgasmic women, or at least a very large proportion of them, are potentially multi-orgasmic, and some women can have very long duration orgasms, termed a status orgasmus by [31] (see Chapter 7). Male orgasm, once triggered, is inevitable, but in women, if physical stimulation is stopped just prior to when an orgasm would normally occur, the orgasm does not happen [52]. The pattern of orgasmic contractions also differs, with men displaying a pattern not observed in women [53; see Chapter 7].

Whilst orgasm in men is almost always indicated by ejaculation, or at least the muscle responses normally associated with it, and of course, variously intense sensations, coming up with a scientific definition of female orgasm seems to have been rather more difficult. Back in 1970, Clark [54] wrote:

"... as I am sure we all agree, we mean the convulsive, rhythmic contractions of the pelvic musculature commonly accompanied by the highest peak of pleasurable feeling as a climax to sexual stimulation. This usually results from petting, caressing, and manual or penile stimulation of the vulva, clitoris, and vagina."

The following effective definition, which was proposed by Meston et al. [37] is one of the easiest to apply:

"A woman’s orgasm is a variable transient peak sensation of intense pleasure, creating an altered state of consciousness, usually accompanied by involuntary, rhythmic contractions of the pelvic striated circumvaginal musculature, often with concomitant uterine and anal contractions and myotonia that resolves the sexually-induced vasocongestion, usually with an induction of well-being and contentment."

Numerous other researchers and physicians have also provided definitions or descriptions of orgasm; see Mah and Binik [55] for a partial list. Many of those referring to female orgasms mention genito-pelvic muscle contractions, but this is a little problematic because they do not occur (at least conspicuously) in all women when they subjectively experience an orgasm [31: p. 34].

Do all women know when they have an orgasm? Men might think so, but apparently, the female of the species is not always so sure [56, 57, 58]. In these studies, between 12 and 29% of women reported that they were unsure as to whether they experienced orgasms or not.

Female sexual physiology is much more complex than that of male, and the scientific investigation of it has undoubtedly been discouraged by cultural and religious considerations [59]. Thus, researchers broaching this 'taboo' topic deserve applause. The likes of Dickinson, Kinsey, Masters, Johnson, Hite and many others, especially those working before the pill-enabled sexual revolution of the 1960s, deserve great credit, because many or most of them received little approbation and much disapproval from the general public, medical and scientific communities. That those with university posts actually found little difficulty recruiting experimental subjects from the female student population highlights the latter's understanding that their sexuality was a woefully neglected area of study.

References